This paper enhances the defender model by explicitly modeling the cost associated with quality attributes. It considers two firms and two quality attributes which cause fixed and variable cost, respectively, together with the price attribute. Hence, firms compete in three dimensions. The optimal...

Increased direct and indirect competition in the postal sector represents a great challenge to the traditional business model of postal operators. It is often put forward that regulatory institutions need to evolve in parallel and coherently with developments in the market place in order to...